System and apparatus for transfer of personnel/cargo between a marine platform and crew boat

ABSTRACT

The present disclosure is directed to a system and apparatus for employing the compressibility of a gas (air) to provide a variable length, load carrying, member in a suspension system used for transporting a load (personnel, cargo, provision, etc.) from one point to another, between which points there is relative motion. This device incorporates the foregoing basic idea into a system which eliminates relative oscillatory motion between a load and an oscillating point to which the load is being transferred, while allowing relative linear motion between the load and the oscillating point.

United States Patent [1 1 Begault [451 Feb. 26, 1974 SYSTEM AND APPARATUS FOR TRANSFER OF PERSONNEL/CARGO BETWEEN A MARINE PLATFORM AND CREW BOAT [76] Inventor: Rudolph A. Begault, 1717 Disney Dr., Metairie, La. 70003 [22] Filed: Nov. 22, 1972 [21] Appl. No.: 308,825

[52] US. Cl. 214/14 [51] Int. Cl B65g 67/58 [58] Field of Search ..214/12,13,14,l5 R

[56] References Cited UNITED STATES PATENTS 2,854,154 9/1958 Hepinstall 214/14 2,998,148 8/1961 l-limel, .lr.; 214/14 3,512,657 5/1970 Chambers 214/13 X Primary Examiner-Frank E. Werner Attorney, Agent, or FirmWilkinson, Mawhinney &

Theibault [5 7] ABSTRACT The present disclosure is directed to a system and. apparatus for employing the compressibility of a gas (air) to provide a variable length, load carrying, member in a suspension system used for transporting a load (personnel, cargo, provision, etc.) from one point to another, between which points there is relative mo tion. This device incorporates the foregoing basic idea into a system which eliminates relative oscillatory motion between a load and an oscillating point to which the load is being transferred, while allowing relative linear motion between the load and the oscillating point.

6 Claims, 6 Drawing Figures 'PAIENTED F5526 4 SHEET 3 0F 3 I ROPE NETTING PROBLEMS IN AND STATE OF THE ART Apparatus now in use for transferring personnel or cargo from a platform at sea to an adjacent vessel is as follows: I

The hook from a crane on the platform is passed through a steel ring to which a large net has been attached. The personnel get into the net and are lowered over the side by the crane. A crew boat is positioned below the net. The crane operator estimates the height above the boat at which he should stop lowering the net. He must keep the net high enough so that the boat deck does not smash into it and the crew as the boat rises on the waves. He must, likewise, get the net low enough so that the crew can jump from the net to the boat deck as the boat rises. It is then incumbent upon the crew to time their jump so that the boat is not falling in another wave before they reach the deck. The

positioning of the landing spot" (onthe boat deck) is governed entirely by the expertise of the boat operator in rough seas, even the best operators have limitations. I

Three distinct hazards are apparent in the prior art: l. The vertical positioning of the net aedvsm'eeoat;

2. The relative oscillatory motion between the boat deck and the net.

3. The lateral positioning of the landing spot for the crew.

The present invention eliminates the above hazards.

An object of the present invention is to provide a personnel transfer system and apparatus in which the personnel transfer basket has a self-contained closed circuit pneumatic system for stroking a long actuator in to ft. strokes, that is the rod extending from the cylinder the base of which is secured to the personnel transfer basket or container. The closed system has reservoir tanks in circuit with the actuator which may be charged at either the platform or crew boat to compensate for varying weight to be transferred.

A further object of the present invention is the provision of a closed circuit system of a compressible medium of gases such as air in which the medium will compress and expand to control the stroke of the rod within the cylinder the bottom of which is secured to the personnel transfer basket which is pulled to the deck of the crew boat by a winch against the fixed hold of the platform crane at the upper end of the piston rod.

With the foregoing and other objects in view the invention will be more fully described hereinafter and more particularly pointed out in the appended claims.

In the drawings in which like parts are denoted by reference characters throughout the several views:

FIG. 1 is a perspective view of a personnel transfer cage on its stowage pedestal showing the actuator cylinder and the containers of the closed pneumatic circuit with external charging connection.

FIG. 2 is a side elevational view of the personnel transfer cage or basket of FIG. 1 connected to its raising and lowering crane and removed from the stowage pedestal.

FIG. 3 is a side elevational view of FIGS. 1 and 2 shown relative to the crew boat to which and between which personnel will be transferred.

FIG. 4 is a side elevational view of the personnel basket of FIGS. 1, 2 and 3 being winched down to the crew boat.

FIG. 5 is a side elevational view of the personnel transfer basket showing containers,'actuator and charging connection for closed pneumatic circuitry as well as 0 the safe return valve, its interconnecting tubing and an optional on board pressurization system.

FIG. 6 is a vertical sectional view taken through the safe return valve.

Referring now to the drawings, the principal application of this device is in the transfer of personnel or cargo from a relatively stationary platform 10 at sea, such as an oil production platform, to an adjacent crew boat or cargo boat 11 which is oscillating due to wave action.

With the personnel cage or basket 12 at rest on the platform deck 10, FIG. 1, and quick disconnect couplings 13, FIG. 5,.uncoupled, the load (personnel and- /or cargo) is put aboard.

Valve 14 is opened thus venting the system. With the system vented, crane hook 15 is shackled through rod end eye 16 and crane cable 17 is taken up. Since the weight of the cylinder 21 and cage 12 (loaded or empty) exceeds the internal friction of actuator assembly 18, rod 19 will extend as cable 17 is taken up. With rod 19 extended approximately 2 ft., crane cable 17 is stopped and locked.

Valve 1.4 is closed and couplings 13 are connected and the high pressure air source is activated. Valve 14 is then opened, thus admitting high pressure air to the system. When gauge 20 reaches the proper predetermined pressure, valve 14 is closed, thus isolating the pressure in the system. The predeterminedpressure in cylinder 21 is sufficiently excessive to overcome the maximum anticipated load and to thereby raise the cage 12 and load from the platform deck 10. Cylinder 21, with thecage 12 will be driven to its uppermost stop position on rod 19. With the assembly suspended approximately 2 ft. above the deck 10, couplings 13 are decoupled. Crane cable 17 is taken up, raising the assembly 12 to a height sufficient to clear railings, etc. and deadline 22 is secured to safe return valve 23. The assembly with attached deadline 22 are then swung over the side.

With a crew boat 11 positioned below the cage 12, crane cable 17 is paid out until the assembly is approximately one-half times the average wave height above the boat at its highest pitch. At this point, crane cable 17 is stopped and locked. The free end'of deadline 22 (approximately 30 feet long) is retrieved by a crew member of the boat 11 and passed through boat idler pulley 24 and attached to boat winch -25. Suff cient slack is maintained in deadline 22 to preclude unexpected loading of deadline 22 while the above operation is in progress. Deadline 22 is taken up on boat winch 25. The downward pull of deadline 22 pulls cylinder 21 and the attached cage 12 with its load down.

I With rod 19 restrained by crane cable 17, the trapped air in cylinder 21 is compressed to a higher pressure sufficient to raise the cage 12 and load as the boat 11 rises on the sea. As the assembly is winched toward the boat 11, it will rise due to the pressure in cylinder 21 and lower due to the pull of deadline 22 with the boat 11 subject to wave action thus eliminating relative osciliatory motion between the cage 12 and the boat 11. Continued winching of deadline 22 will lower cylinder 21 and attached cage 12 thus allowing relative linear motion between the cage 12 and the boat 11. When the cage 12 reaches the boat 11, it will continue to move with the boat, thus providing a secure iandhold and a fixed height step-down for the personnel.

Also, the landing spot for the assembly is fixed by the location of boat idler pulley 24.

To return the cage 12 from the boat 11 to the platform with more or less load, provided the maximum anticipated load is not exceeded, boat winch is reversed thus allowing the pressure in cylinder 21 to raise the cage 12 back to its original position, one-half the average wave height above the boat deck. At this point, deadline 22 is made free of boat winch 25 and the cage 12 with its load is returned to the platform by the crane 17A.

The safe return valve is provided to preclude severe upward acceleration of cylinder 21 and cage 12 should deadline 22 fail or be cut when the unit is at maximum or near maximum extensions and high (return) pressures are developed within the actuator. Under the above conditions, without safe return valve 23, the unit would be driven upward, slamming the piston into the lower head of cylinder-21 thus dislodging the crew and possibly damaging the actuator. The principle of the valve is to restrict the flow of air from the vent ports of cylinder 21 when the deadline load is removed.

The valve consists of four basic parts: flange 28, body 29, poppet 30, and spring 31.

Flange 28 is a plate suitably sized and drilled to match attaching lugs on the lower head of actuator 18. Body 29 is a cylinder containing two sets of diametrically opposing ports 32 and 33 and internally machined to accommodate poppet 30 and spring 31. Poppet 30 is slidable within body 29. 1t has a tapered conical upper end, a shoulder and provides a means for attaching deadline 22 at the lower end. Spring 31 is a coil spring which bears aginst the underside of the shoulder on poppet 30 and is contained within the appropriate cavity in body 29. Spring 31 is sized to provide a positive upward force on poppet 30.

Cylinder 21 suction/vent ports 34 are connected to valve ports 32 by tubing 27. When the unit is in the process of being retrieved by the boat, there is a positive downward force on deadline 22. This force is sufficient to compress spring 31 and move'poppet 30 down until the poppet shoulder bottoms against the body shoulder thus providing a clear passageway between valve body ports 32 and 33. Ports 33 being open to the atmosphere. Under normal operating conditions, free air passage between these ports is essential to prevent pressure or vacuum from developing in the lower end of cylinder 21 thus causing the unit to respond in a sluggish manner.

If deadline 22 fails or is cut, spring 31 immediately returns poppet 30 to the up position thus causing a restriction between body ports 32 and 33. This restriction provides a limited exit of air from the underside of cylinder 21, thus causing a pressure increase in the lower end of the actuator which opposes the pressure in the upper end of the actuator. The conical taper at the upper end of poppet 30 is sized to permit the proper flow of air from cylinder 21 vent ports 34 such that the unit will rise on rod 19 at a retarded rate thus providing a snubbing effect in actuator 18. Poppet 30 is provided with the tapered conical upper end rather than ports for the purpose of eliminating port alignment as poppet 30 is free to rotate within body 29. I

The optional on board pressurization system is provided to boost the pressure of the closed circuit pneu' matic system at the boat in instances where the load to v be transferred from the boat exceeds the maximum load for which the unit was pressurized at the platform. The on board pressurization system system is pressurized at the platform, using the regulated air supply.

With couplings 13 connected and the high pressure air source activated, valves 14 and 36 are opened admitting high pressure air to container 35 through interconnecting tubing 37 which is connected to the actuator charging tubing. When gauge 20 reads the appropriate pressure, valves 36 and 14 are closed and the high pressure air source is stopped. Couplings 13 are disconnected and valve 14 is opened, venting the closed pneumatic actuator circuit while retaining the pressure in the on board pressurization system. Should additional pressure be required in the closed pneumatic actuator circuit while the unit is at the boat, valve 36 is opened thus boosting the pressure in that circuit.

The mathematics of charging the closed circuit system with containers 26 is governed and controlled by the fact without containers 26 P becomes too large, too fast. A closer look at P,V, P V reveals the following:

or P,V /V P which shows that P is a function of P and the ratio of V,to V

since P is required to balance the load, V,/V must be reduced this is the purpose of containers 26 Thus: Piston area 50 in.

L load (assembly personnel) 2000 lbs.

S stroke 144 in.

Volume of container 26 30,000 in.

Volume of cylinder 21 alone 7,200 in. To react (balance) aload of 2,000 lbs. required a pressure in cylinder 21 and container 26 of:

F=PA

40psi=P 40 psi is the pressure (P,) in cylinder 21 and container A 26. With zero stroke V volume of cylinder 21 container 26 V 7,200 30,000 37,200 in.

Assuming a in. stroke V remaining volume of cylinder 21 container 26 V 1,200 30,000 31,200 in.

Then applying P,V V

40 X 37,200 P X 31,200 71503 7150631 ,Q'OO E I 47.74 psi P Therefore the force developed in deadline 22 as a result of this increased pressure is: F PA F 47.74 X 50 2390 lbs -2000 lbs/390 lbs load ing a piston and rod, said cylinder being secured at its closed end to said transfer means so that the piston rod 1 is extendable above the transfer means for connection to the crane, pneumatic reservoir means connected in closed fluid circuit with said pneumatic cylinder, means connected in fluid circuit with said pneumatic cylinder to charge same causing the cylinder to stroke and raise the transfer means and its load above the platform, down haul means releasably connected to the closed end of said cylinder and being connectable to a winch on the crew boat to pull the load transfer means and its load to the deck of the crew boat.

2. A load transfer device as claimed in claim 1 wherein the operating pressure within the pneumatic cylinder multiplied by the area of the piston exceeds the maximum anticipated load.

3. The method of transferring personnel and equipment between an off-shore rig and a crew boat in a load transfer means comprising subjecting the transfer means to a pneumatic force from a closed pneumatic precharged system sufficient to lift the transfer means and its load above the deck of the rig, mechanically lowering the transfer means toward the crew boat to within 1/2 the average wave height, thereafter mechanically pulling the transfer means toward the crew boat compressing the closed pneumatic system so that the transfer means will ride with increased pressure within the closed pneumatic system and lower with the crew boat riding the waves to damp out and eliminate relative oscillatory motion between the transfer means and the crew boat.

4. The method of claim 3 wherein the closed pneumatic system is precharged to a value sufficient to raise the transfer means and its load above the deck of the rig before mechanically lowering the transfer means toward the crew boat.

5. The method of claim 4 wherein the closed pneumatic system is precharged at the crew boat to compensate for any increased load on the return trip from the boat to the rig.

6. A load transfer device as claimed in claim 1 further comprising a safe return valve in pneumatic circuit with the cylinder between said cylinder and down haul means.

' UNITED STATES PATENT OFFICE v CERTIFICATE OF CORRECTION Patent No. 3v794'l87 Dated February 26, 1974 Inventor RUDOLPH A BE GAULT It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 61, change "P2' to -P Column 5, line 1 and 2, change "F 47.74 x 50 2390 lbs 2000 lbs/390 lbs load" to -F 47.74 x 50 239o# -2000# load Signed and sealed this 16th day of July 1974.

(SEAL) Attest:

MCCOY M. GIBSON, JR. C'. MARSHALL DANN 'Attesting Officer Commissioner of Patents USCOMM'DC 60376-PU9 U.S. GOVERNNEIQTPII'ITING OFFICE Z 1.. 0-366-334,

FORM o-wso (10-69) 

1. For use between a marine platform having a crane and a crew boat a load transfer device comprising transfer means, an elongated pneumatic cylinder having a piston and rod, said cylinder being secured at its closed end to said transfer means so that the piston rod is extendable above the transfer means for connection to the crane, pneumatic reservoir means connected in closed fluid circuit with said pneumatic cylinder, means connected in fluid circuit with said pneumatic cylinder to charge same causing the cylinder to stroke and raise the transfer means and its load above the platform, down haul means releasably connected to the closed end of said cylinder and being connectable to a winch on the crew boat to pull the load transfer means and its load to the deck of the crew boat.
 2. A load transfer device as claimed in claim 1 wherein the operating pressure within the pneumatic cylinder multiplied by the area of the piston exceeds the maximum anticipated load.
 3. The method of transferring personnel and equipment between an off-shore rig and a crew boat in a load transfer means comprising subjecting the transfer means to a pneumatic force from a closed pneumatic precharged system sufficient to lift the transfer means and its load above the deck of the rig, mechanically lowering the transfer means toward the crew boat to within 1/2 the average wave height, thereafter mechanically pulling the transfer means toward the crew boat compressing the closed pneumatic system so that the transfer means will ride with increased pressure within the closed pneumatic system and lower with the crew boat riding the waves to damp out and eliminate relative oscillatory motion between the transfer means and the crew boat.
 4. The method of claim 3 wheRein the closed pneumatic system is precharged to a value sufficient to raise the transfer means and its load above the deck of the rig before mechanically lowering the transfer means toward the crew boat.
 5. The method of claim 4 wherein the closed pneumatic system is precharged at the crew boat to compensate for any increased load on the return trip from the boat to the rig.
 6. A load transfer device as claimed in claim 1 further comprising a safe return valve in pneumatic circuit with the cylinder between said cylinder and down haul means. 